Interlocking system for railroads



Oct. 8, 1940. N. o. PRESTON ET AL 2,217,206

INTERLOCKING sYs'rnM won izAlLnbAns Filed June 12,1937 11 Sheets-Sheet 1 FIG- 1. A.

l I I 'l 'l l I I I I Ila-h I I I {I Clearor Stop fitaitl'on Selecting 1' l Elements I Contacts and Selections l2ou1'e Similar to those for Elements Route Relay 5"@ Direction 4/. INVENTORS 1 NIDPres'ton and EBHitchcack BY 128 THEIR ATTOR NEY Oct. 8, 1940- N. D. PRESTON ET AL 2,217,206

INTERLQCKING SYSTEM FOR RAILROADS' Filed June 12, 193' 11' Sheets-Sheet 2 FIG.1.B.

- INVENTORS YNDPreston and EBHitchcock THEIR ATTORNEY Oct. 8, 1940. N. D. PRESTON ET AL 2,217,206

INTERLOCKING SYSTEM FOR .K ILRoADs Filed June 12, 193 .11 Sheets-Sheet 3 LLEL Lg onnected at Last Statfon INVENTORS TL YNDPreston and Ffifiitchcock THEIR ATTOR'NEY Oct. 8, 1940. N. D. PRE$TQN ET AL, 2,217,206

INTERLQCKING SYSTEM FOR RAILRQADS Filed June 12,193 1 Sheets-Sheet 4 mas.

W 1 2-52 5-212 C-)- Fc-J 2-412 1 If" 1 F F I L] I l 21 505 i i l f I i l l l gee l l lNVENTORS NDPrescon and FBHiEchcock TH E172 ATTORNEY Oct. 8, 1940. N. D. PRESTON El AL, ,2

m'rmnocxme SYSTEM F R-aAI-moms Pi-led-June-lif'i? 11 Sheets-Sheet s Fla. 2Q.

INVENTORS NDPresTon and FBHitchcock THEIR ATTORNEY N. D. PRESTON Er AL INTERLOCKING SYSTEM FOR RAILROADS Filed June 12, 1937 Sheets-Sheet 7 INVENTORS NDPreston and FBHitchcock BY MM M THEIR ATTOR.NEY

FPS

(R 28 &

Oct. 1949. N. D. PRESTON ET AL 2,217,296

INTERLOCKING SYSTEM FOR RAILROADS Filed June 12, 193' 11 Sheets-Sheet 8 INVENTORS B NDPreston and EBHitchcock THEIR ATTORNEY Oct. 8, 1940. N. D. PRESTON ET AL 2,217,206

INTERLOUKING SYSTEM FOR RAILROADS Filed June 12-, 1937 ll Sheets-Sheet 9 CN) (cw) I K FIG-.4. 4x15 4NB cw c N cm YNK 72K 9NK 912K ,To 25c I I 24c {q INVENTORS I NDPreston and EBHItchcock BYMMW THEIR ATTORNEY Oct. 8,-1940. N. n. PRESTON ET AL 7,

INTERLOCKING SYSTEM FOR RAILROADS Filed June- 12, 193'! 11' Sheets-Sheet 10' Fla 5 NVENTORS I 'W( NDPrestonand EBHitchcock THEIR ATTOR'NEY 1940- N. D. PRE-STON El AL 2,217,205

INTERLOCKING SYSTEM FOR RAILROADS v Filed June 12, 193v- 11' Sheets-Sheet 11 INVENTORS NDPreston and FBH itchcock THEIR ATTORNEY Patented Oct. 8, 1940 antics 2,217,206 INTEBLLOCKING SYSTEM FOR. a ILnoAns Neil l). Preston, Rochester, and Forest B. Hitchcock, Greece, N. Y., assignors to General Railway Signal Company, Rochester, N. Y.

Application June 12, 1937, Serial No. 147,876

33 Claims.

This invention relates to interlocking systems for railroads, and more particularly pertains to an interlocking system in which a miniature track layout in a control oiiice has located thereon the controlling buttons or levers for setting up the desired routes through the actual track layout by manipulations of the entrance-exit route type as distinctive from the type of system using an individual control lever for each trafiic device controlled.

The present invention relates to improvements,

gram, while the end of each route has associated therewith a completing (or exit) button. To establish a particular route over the trackway, the operator actuates the initiating button at the entrance to such desired route and then actuates the completing button for the exit end ofthat route, followed by the actuation of a starting button for initiating the code type communication part of the system into operation. I

The entrance-exit manipulation of the initiating and completing buttons for a particular route sets up a route code characteristic of that route, which code is transmitted to the apparatus in the field by a code type communication system, which may be of any suitable type, but for convenience has been considered to be of the type shown in the prior patent of Judge and Bushnell Patent No. 2,082,544, granted June 1, 1937.

, Inasmuch as such a communication system can transmit only a single code during any one cycle of operation, the system of the present invention allows only one route code to be set upon the control panel at any one time. When such a desired or proposed route has been set up on the control panel, suitable indicator lamps, preferably of a bluish white, are provided to illuminate the proposed route on the miniature track diagram to leave a visual record of the operators manipulation. After the system has transmitted the route code for that particular route and the trafiic devices have actually responded, suitable indications are transmitted back to the control ofiice to cause the proposed routeindicators to be extinguished and other suitable completed route indicators to be illuminated on the track diagram to indicate the route actually set up. These completed route indicators are preferably of a red color so as to advise the operator by a distinctive indication that no route can be set up in conflict with such sompleted route.

In the event the operator should ill-advisedly set up a proposed route upon the control panel in conflict with a route already established in the field, the system will cause the transmission of the route code for the proposed route, but suitable interlocking means are provided at the field location to prevent such proposed route code from being eifective to either establish its route or to interfere with the route already established. The failure of such proposed route to become eifective prevents the storage of any controls at the field location which might at a future time set up such proposed route; and similarly, the system having transmitted such proposed route code cancels the storage of its related controls in the central oflioe. In order to set up such proposed route at a later time, a new set of manipulations is required for such route.

However, it will be noted that the proposed route indicators on the control panel remain illuminated under such circumstances, so that the failure of such proposed route indicationsto be 3 transferred to completed route indications ad- Vises the operator of the actual conflict between routes, at which time he can take such action as may be-deemed expedient. These proposed route indications can, of course, be extinguished at any time by the operation of a cancelling button.

A similar manipulation is employed, when the operator desires to return a route to stop. He

'first actuates a stop button and then designates the route which is desired to be put to stop by actuating the entrance button and the exit button for that route. The transmission of the stop route code thus set up is initiated vby'the operation of the communication system starting button. The reception of this stop route code by the field apparatus causes such route to be returned to stop, and the transmission of tions to the control office. 1

The entrance-exit method .of control or manipulation so characterizes the system of the present invention, that it has been aptly termed entrance-exit interlocking, or abbreviated as NX interlocking. Other objects, purposes, and characteristic features of the present invention Will be in part obproper indicavious from the accompanying drawings, and in part pointed out as the description of the inven-.

tion progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which like reference characters designate the same parts throughout the several views; in which like letters in the reference characters designate similar functions or relationships with the distinctiveness between such reference characters provided by the use of distinctive preceding numerals; in which like preceding numerals in the reference characters, when applied to different letters, represent the inclusion of such devices within a particular group and in which:

Figs. 1A and 113-, when placed side by side, illustrate the circuit arrangement employed in connection with the system of the present invention for setting up the route control codes for transmission over the multiple impulse code type of communication system;

Figs, 2A and 23, when placed end to side together with Figs. 2B, 2C and 2D placed side to side, represent the decoding apparatus employed at the field location for controlling the individual trafiic governing devices in accordance with the route control codes received over the communication system;

Figs. 3A and 313, when placed end to end, represent the indication transmitting and receiving parts of the code type communication system for the field station and control office respectively;

Fig. 4 illustrates the manner in which the indications received over the code type communication system are effective to control the indicating lamps associated with the miniature track diagram and control panel illustrated in Fig. 1A;

Fig. 5 illustrates certain parts of the code transmitting apparatus employed in the control office; and

Fig. 6 illustrates certain parts of the code transmitting apparatus employed at the field location.

Instead of showing the complete circuit arrangement by placing a large number of sheets side by side, a simplified method of disclosure has been employed wherein all of the control circuits for any one relay are shown in a continuous relationship; while all of the circuits which that relay may control are distributed between several sheets upon which that relay is shown in block form.

For the purpose of further simplifying the illustration and facilitating in the explanation thereof, the conventional parts and circuits constituting the embodiment of the invention have been,shown diagrammatically and certain conventional illustrations have been employed, the drawings having been made more with the idea of making clear the purpose and principles of the present invention, together with its mode of operation, than with the idea of illustrating the specific construction and arrangement of parts that would probably be employed in practice.

The various relays and their contacts are illustrated in a conventional manner and symbols are employed to indicate connections to the terminals of batteries or other suitable sources of electric current supply instead of showing all of the wiring connections to such terminals.

The symbols and are employed to indicate the positive and negative terminals of suitable batteries or other sources of electric en ergy; and those terminals with which such symbols are used are presumed to have current flowing from the positive terminal designated (-1 to the negative terminal designated l I The symbols (3+) and (B) indicate connections to the opposite terminals of a suitable battery, or other direct current source, which has a central or intermediate tap designated (CN) and the circuits with which these symbols are used may have current flowing in one direction or the other, depending upon the particular terminal used in combination with the intermediate tap The symbols employed with any one circuit are considered to designate the terminals of the same battery or other suitable source, but as many separate sources may be used as found necessary in the practice of the invention. If alternating current is employed, then these symbols should be considered to representthe instantaneous relative polarities of the respective terminals.

Where. groups of devices are referred to in a general way, such devices will be designated by the letters or preceding numerals characteristic of such groups instead of citing each specific reference character of such groups.

Track layout Fig. 2D.In the accompanying drawings, the invention has been shown applied to a track layout including a stretch of double track connected by a cross-over having track switches ITSA and 'ITSB, as well as including a diverging track connected to one of the main tracks by a track switch HTS. The stretch of double track includes a main line extending from a signal 2 to a signal 5, and another main line extending from a signal 3 to a signal 6. Signal 4 governs traflic from the diverging track over the track switch STS.

Inasmuch as the opposite ends of a crossover are usually operated at the same time, the crossover is considered as operated by a single switch machine SM, which may be of any suitable type, such, for example, as disclosed in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923. However, two switch machines may be employed if desired.

It is to be understood that the invention is not limited, as thus shown, to the control of a crossover and signals of this chosen track layout, but may be applied to any desired number of switches and signals and to all types of track layouts found in interlocking plants.

The signals 2, 3, 4, 5 and 6 are assumed to be color light signals giving the usual indications of green for clear, red for danger or stop, and, if an added indication is desired, yellow for caution. These signals may be of the color light type, or any other suitable type.

The control for the signals is accomplished through the signal relays 2G, 3G, 4G, 5G and 6G in the usual way, so that each signal indicates stop when its respective G relay is deenergized and indicates clear when it is-energized.

The track layout of Fig. 2D has been shown divided into track circuit sections I and 8 by suitable insulated joints indicated in the usual manner. These track sections are provided with the usual track batteries and track relays of which only the track relays IT and 8T have been shown. These normally energized track circuits are wired in the usual manner to provide for fouling protection and to provide for the insulation of the crossover and track switch, such details of wiring having been omitted for the sake of simplicity in the disclosure. These track circuits can of course be divided or lengthened as desired, and arranged in accordance with any of the usual practices.

The track relays IT and BT have respectively associated therewith slow acting repeating relays IT]? and 8TP for reasons more specifically pointed out hereinafter.

The crossover including the track switches ITSA and 'ITSB is shown as operated by the switch machine ISM and has associated therewith a switch position repeating relay lWP (see Fig. 2B); while the track switch QTS is shown as operated by the switch machine 9SM and has associated therewith the switch repeating relay 9WP. Each of these switch position repeating relays WP is of the polar neutral type and is energized with one polarity or the other in accordance with the normal and reverse locked positions of its associated track switch TS and switch machine SM, and is deenergized wheneverv its associated track switch TS is unlocked or is in operation. Such a polarized circuit for controlling a switch position repeating relay is governed through the medium of a point detector contact mechanism, such as shown, for example, in the patent to C. S. Bushnell, Patent No. 1,517,236, dated November 25, 1924.

Control pcmel.ln the central ofiice, av control machine includes a control panel on which is located a track diagram corresponding to the actual track layout in the field. The track diagram has been shown in Fig. 1A as specifically related to the control features of the present invention; and has been shown in Fig. 4 as specifically related to the indication features of the present invention. Both Figs. 1A and 4 are to be considered as the same diagram, and have been shown as having a miniature cross over its and a miniature turn out switch Sits. These miniature track switches have associated therewith i1- luminated portions of trackway which may be constructed in a manner similar to that shown in the prior application of F. B. Hitchcock, Ser. No. 74,709, filed April 16, 1936, but are illuminated in accordance with the present invention.

On this control panel are suitable entrance buttons NB, one for each of the signal locations, so that entrance buttons ZNB, 3N3, 4NB, 5N3 and SNB correspond respectively to the locations for signals 2, 3, 4, 5 and 63. Also, an exit button X3 is provided for the end of each route, shown as buttons ZXB, 3X3, 4X13, 5X13 and GXB. It is to be understood that the ends of the routes may or may not correspond to the location of the exit buttons on the miniature track diagram, as a route is usually considered to extend from one particular signal to the next signal for the same direction or to some arbitrarily chosen point.

1 Each entrance button NB is in the form of a. knob which is rotatable from a normal biased position to a position where the index arrow on the knob is parallel to the miniature trackway and is pointing in the direction in which the route is to be cleared. When an entrance but ton NB is in an operated position, it energizes an associated repeater relay NR throughcircuits directly controlled by contacts operated by the entrance button NB, indicated in the drawings by dotted lines. In other words, each entrance button is of the self-restoring rotatable type and always assumes a normal inactive position, but when operated to an active position effects the control of a repeater relay which is provided with a stick circuit to maintain such control although the operator releases the entrance button.

The exit buttons XB are of the self-restoring push button type and operate contacts which have been shown in the drawings as connected to the buttons XB by dotted lines. These exit buttons XB may be made visually distinctive from the entrance buttons by making them of a different color or the like, but in accordance with the present invention, it is: contemplated that the only difference in this respect is in the index on such buttons which is provided in the form of an X.

Associated with the entrance and exit buttons for each signal location is a suitable signal indicator K having suitable preceding numeral to indicate the signal with which it is associated. These indicators are preferably illuminated only when their corresponding signals are cleared as shown in Fig. 4.

The entrance button repeater relays NR together with the exit buttons XB control and select suitable route relays. These route relays have been designated: route relay (*l-t for controlling trafiic over the main line track from signal 3 to signal 6 in both directions; route relay 3-5 for controlling trailic in both directions between signals 3 and 5; route relay 25 I for controlling. trafiic in both directions between signals 2 and 5; route relay 3& for controlling traflic in both directions. between signals 3 and 4; and route relay 2--4 for controlling traffic in both directions between signals 2 and i.

These route relays have associated therewith a route stick relay RS for allowing only one route relay to be energized at a time. These route relays, such as route relay 3--6, control the setting up of the route control codes which are transmitted over the code type communication system to the apparatus in thefield.

Also located on the control panel in a convenient position are the buttons ST, CA and ST? which are common to the whole system.

The start button ST is for starting the code type communication system into operation and efiects this throughthecontrol of a change storing'repeating relay CHP. 1

The'cancelling button CA cancels any route at any time which has been set up between entrance and exit buttons NB and KB.

The stop button STP is provided. for changing the route control code set up by any conibina tion of entrance and exit buttons from a clearing code to a stop code. This stop button is preferably operated before the particular route to be put to stop has been designated by the entrance and exit buttons NB and KB. This stop button STP has associated therewith a stop route relay SR.

Communication part of the system.--It is to be understood in connection with the communication part of the system shown in Figs. 1B; 2A, 3A, 3B, 5 and 6 that reference should be made to the prior-Patent No.-2,082,544 granted to Judge and Bushnell on June 1, 1937, for an exhaustive description of such code type'communication system, only those parts of such description being pointed out herein as is deemed necessary for an understanding of the present invention. For convenience in comparing the parts of the present disclosure corresponding to the parts of such prior application, the same reference characters have been employed in this disclosure as were used in such prior application. Also, certain relays have been shown in block form without control circuits, but it is to be understood that these relays are controlled as shown in the above mentioned prior application. i

To simplify the disclosure of the present invention, the line circuits and their related control relays at the control ofiice and field station have been shown in Figs. 5 and 6, together with the stepping banks which are operated in synchronism. In other words, these figures showthe interrelation between the stepping-control line circuit and the indication line circuit.

But a discussion of the invention readily divides itself into two main divisions, namely, transmission of control codes and transmission of indication codes. Therefore, the control part of the system is shown in Figs. 1A, 1B, 2A, 2B, 2C and 2D where certain portions of Figs. 5 and 6 are of necessity repeated. Likewise, the indication part of the system has been shown in Figs. 3A and 33 where certain portions of Figs. 5 and 6 are also repeated. Fig. 3A, however, does not show the details of every indication relay and the circuits which they control, but only shows typical ones. Then in Fig. 4 all of the indication relays and the circuits for the indicator lamps which they control have been shown in connection with the track'diagram.

Although the present invention is contemplated as employed in connection with a communication system of the duplex type, that is, a system which provides for the simultaneous transmission of controls and indications when both are ready for transmission, it is to be understood that any suitable communication system either of the duplex type or of the simplex type may be employed, and that the system is not limited as shown toa communication system employing two separate circuits for controls and indications respectively.

A transmitting and receiving equipment is located in the control oifice and another such equipment is located at each of the field stations. The control ofiice and field stations are connected by a stepping and control line circuit and an indication line circuit.

The control and stepping line circuit is shown as including line wires and I2 connecting the control ofiice apparatus shown in Fig. 13 with the field station apparatus shown in Fig. 2A.

' The line wire I0 is shown as including a threeposition biased-to-neutral polar line relay F at the control oifice and a similar line relay F at the field station. This control and stepping line circuit receives polar impulses as applied from a control battery CB by the pole changing contacts ,50, 53 and 54 of the relays PC and NC, to-

gether with an impulsing contact 52 of an impulsing relay EP.

The indication line circuit is shown as including line wires I4 and I6 which connect the control office apparatus shown in Fig. 3A with the field station apparatus shown in Fig. 3B. This indication line circuit receives energy from the indication battery 13 and has associated therewith two message receiving relays MF and MB which respectively receive the messages transmitted during the impulse and time space periods marked off on the control line circuit. At the field station the indication line circuit has associated therewith a lockout relay L0 having 'a contact I56 included in the line wire M for determining when that field station is to transmit indications. The indications are transmitted by relays PF and PB respectively during the impulse and time space periods marked off on the control line circuit.

The transmitting apparatus at the control office energizes the stepping and control line circuit with a series of time spaced impulses of polarities selected in accordance with the station and route codes to be transmitted as set up by the manipuon the miniature track diagram. Each of these series of time spaced polar impulses comprises a predetermined number of impulse and time space periods to cause a complete operating cycle of the system. At the beginning of each series of impulses, a slow acting relay SA in the control office and a similar relay SA at the field station is picked up. These relays SA are made sufficiently slow acting to be maintained picked up between successive impulses throughout the operating cycle, although their circuits are momentarily opened during each time space period. In the control oflice, the SA relay has a repeater relay ZSA which is also slow acting.

The application of a series of impulses to the stepping and control line circuit causes the operation of the stepping relays V at the control ofiice in synchronism with the stepping relays at each field station, one step for each time space between impulses, while the polarity of such impulses serves to select a particular field station by thepicking up of the relay S0 at that station and to selectively position the relays PS and NS at the selected station for registering the particular route code intended for that station.

The stepping relay bank at the control ofiice includes stepping relays IV, 2V, 3V, 4V, 5V, 6V, IV and LV together with a half step relay VP. These relays are shown in block form in Figs. 1B and 3A while their detail circuits are shown in Fig. 5, and operate in response to the operation.

of the line repeating relay FP in a manner completely shown and described in the prior Patent No. 2,082,544 dated June 1, 1937.

Similarly, the field station includes a stepping relay bank having stepping relays IV 2V 3V 4V SW, SW, 1V and LV together with a half step relay VP These relays are shown in Figs. 2A and 3B in block form while their detail circuits are shown in Fig. 6, and operate in response to the line repeating relay FP Although, as above mentioned, the stepping banks at the control ofiice and at each of the several field stations operate in synchronism, the stepping bank at the control office and the stepping bank at the selected station are the only ones which continue to operate throughout a complete cycle of operation, as suitable means is provided at each of the stations to cause the stepping operation to cease at that station as soon as the station selecting part of the operating cycle passes through a point at which there is no further possibility of that station being selected to receive a route code for such cycle of operation. I

The station selection at the field location is accomplished by a station selecting relay S0 controlled as shown in detail in the prior Patent No. 2,082,544, but as the station selecting part of an operating cycle is completely disclosed in such application, only that part of the control cycle which relates to the transmission of route codes will be discussed in detail herein. It is also to be understood that any other suitable station selecting means may be employed, so that for the purpose of an understanding of the present invention only the apparatus of a single field station need be discussed in detail.

The control oflice communication apparatus also includes an impulsing relay E and its repeating relay EP, a control starting relay C, a field starting relay FC, message receiving relays MF and MB, together with a dividing relay DV.

The field station communication apparatus includes a starting relay CH a'lockout relay L0 lation of the initiation and completing buttonspulsing relays PB and PF, a relay S13 which repeats the slow acting relay SA as well as various other auxiliary relays employed in such a communication system. The operation of these various relays of the communication system will with the present invention, indication codes may i be transmitted on the same cycles of operation that route codes are transmitted. However, when the communication system is at rest, it can be initiated into a cycle of operation for the transmission of indications from a field station to the central ofiice whenever a change in the indication conditions occur at such field station. Such a change in the indication conditions at the field station causes a lockout relay L at such field station to close the indication line circuit to transmit a starting impulse to the central office, which starting impulse causes the initiation of the system to transmit impulses over the stepping and control line circuit to operate the step ping banks of the control ofiice and the field stations in synchronisrn so that during the ensuing cycle of operation indication impulses may be transmitted over the indication line circuit. When the cycle of operation is for the transmission of indications alone, the impulses placed upon the stepping and control line circuit are of such a character as to form a so-called phantom code so that no field station is selected to receive a route code, although the station which is transv mitting indications and the control office operate throughout such cycle.

Keeping in mind this general organization of the complete communication system contem plated in connection with the particular embodiment of the invention illustrated, and particularly that station code calls are transmitted for the selection of a particular station from among a plurality of field stations after which a route control code is transmitted to a particular selected station to control the traiiic governeddevices at such stations, consideration may now be given to an explanation of the manner in which the codes are set up in the central office in accordance with the entrance-exit type of manipulation employed in the present invention.

Operation The system is normally at rest, but may be initiated by the operator at any time for the transmission of route codes, as hereinafter explained. While the system is in this condition of rest, or in the period of blank as such condition is sometimes termed, the stepping and control line circuit is normally deenergized; andsimilarly, the major part of the relays of the system is deenergized. Those relays, which are normally energized, will have their circuits specifically pointed out in detail when their operation and functions are discussed.

Although the track switches ITSA, 'Z'TSB and ETS are usually left in their last operated positions, these track switches have been shown in positions for the passage of main line traffic. The signals are normally at stop and as the signals are illustrated as being of the color light type, it is 'to be understood'that the lower or red indicator of each signal is normally illuminated.

With the track sections l and 8 unoccupied, the track relays 11' and ST are, of course, normally picked up.

Referring to Fig. 1A, all of the entrance buttons NE and exit buttons XB are in their normal positions, because they are biased to such positions, and all of the associated route relays are assumed to be deenergized either because of the acceptance of the lastroute set up by a train or because of the actuatjgn of the cancelling button CA by the operator.

Entrance-exit route interZoclcing.-If, for example, the operator desires to set up a route from the signal to the signal 4, he actuates the entrance button 2N5 ninety degrees in a clockwise direction and then actuates the exit'button lXB which is of the self-restoring push button type.

Following the actuation of the entrance button ZNB and before he actuates the exit button 4X3, he glances along the miniature trackway of such route on the control panel and ascertains whether or not it has portions which are illuminated by the red completed route indicators, thereby designating such portions as included in routes already established and conflicting with the newly proposed route. If such should be the case, he knows that a route cannot be set up in conflict with such indicated route so that he does not actuate the exit button lXB, but rather actuates the cancelling button CA. However, assuming that there are no conflicts indicated by such completed route indicators, the "operator actuates exit button 4X13.

The momentary or temporary actuation of the entrance button 2N3 closes a pick up circuit for the relay 2NR from through a circuit including lever contact 68 in a right hand position, windings of relay ZNR, bus wire back contact 62 of route stick relay RS, back contact 63 of cycle demarking relay SA, wire 82, contact 83 of the cancel button CA, to As soon as e the relay 2NR picks up its contacts in response to such current flow, a stick circuit is closed from through a circuit including front contact 1 6 3 of relay ZNR, windings of relay ZNR, bus wire (it, back contact E2 of relay RS, back contact 63 of relay SA, to wire 82, contact 83 of cancel button CA, to The current which flows in this stick circuit for the relay ENR maintains such relay energized only until a route relay is picked up, or until the system is initiated into a cycle of operation. I

The relay 2- 2 is therefore picked up at the time the exit button iXB is actuated, although the entrance button ENB has immediately restored to its normal biased position, so that an energizing circuit is closed ,ior the route relay 2tl from through a circuit including front contact 65 of relay ilNR, upper winding of route relay 2d, back contact SE of relay iNR, back contact til of exit button lXB, to

As soon as the route relay 2-4 picks up, actuating its polar contacts to right hand positions in response to such current flow, a stick circuit is closed for this route relay from (B+) through a circuit including polar contact 68 in a right hand position, front contact 63 in a picked up.

.BXB is automatically restored to it's normaloposilay RS, which is in series with the stickcircuit for the route relay 24 (also all other route re- ,lays), also picks up and opens its back contact 62 deenergi'zing the stick circuit for the relay ,ZNR. It should be noted in this connection that the resistance of the lower windings of each route relay, such as relay 2-4, must be such that when connected in series with the route stick relay RS, a proper flow of current occurs to maintain that particular route relay picked up, and to also .pick up the route stick relay RS.

If the operator desires to prevent the establishment of such route as represented by this front contact 74 to cause the route relay 2--4 to drop away.

Before considering how a route relay causes the illumination of the proposed route indicators on the control panel and transmission of a route code to apparatus in the field through the medium of the code type communication system. upon the actuation of the starting button ST, let us consider how the energized condition of the route relay 2-4 prevents the picking up of any other routerelay.

If the route relay 2& were not picked up, the actuation of the entrance button 3N3 followed by the actuation of the exit button 5X3 would cause the picking up of the route relay 35. This is accomplished by first picking up the relay 3NR by a circuit closed from through a .circuit including lever contact 13 in a right hand position, winding of relay 3NR, bus Wire 6|, back contact 62 of relay RS, back contact 63 of relay SA, wire 82, front contact 83 of cancel button CA, to Relay SNR is maintained picked up by a stick circuit closed from through a circuit including front contact 16 of relay 3NR, windings of relay 3NR, bus wire 6|, back contact 62 of relay RS, back contact 63 of relay SA, wire 82, front contact 83 of cancel button CA, to

With the relay 3NR picked up, a circuit is.

closed for, the route relay 35 upon the actuation of the exit button 5X3 from through a circuit including back contact 65 of relay 2NR, front contact ll of relay 3NR, upper winding of route relay 35, back contact 84 of relay 5NR, back contact 85 of exit button 5XB, to The current which flows in this circuit causes the polar contacts of relay 3-5 to be actuated to right hand positions and the neutral contacts to be picked up. This closes a stick circuit for the route relay 3-5 from (3+), through a circuit including polar contact 86 in a right hand position, front contact 81, lower windings of relay 3-,-5, bus wire 10, windings of route stick relay RS, back contact H of relay E, wire 12, front contact 14 of cancelling button CA, to (CN). The picking up of the route stick relay RS, of course, deenergizes the entrance relay 3NR by the opening of back contact 62.

However, assuming the route relay 24 to be picked up, the route relay 35 can not be picked up, inasmuch as the route stick relay RS is picked up under such conditions opening the back contact, 62 included in the pick up circuit for the entrance button repeater relay 3NR. In other words, the closure of a stick circuit for any one of the route relays causes the energization of the route stick relayRS which removes energy from all of they entrance button repeating relays NR, and itis obvious a route relay can not bepicked up without a picked up relay NR. Thus, only one route relay for the entire system can be picked up at any one time. This is true even though the system includes a large number of interlocked groups such as shown in Fig. 2D. In other words, if there were two such track 1ay-' outs as shown in Fig. 2D related to each other by being placed end to end, the entrance button repeating relays NR for both groups would include the back contact 62 of relay RS in their circuits, so that only one route relay couldbe picked up at any one time.

It will be observed that track layouts in general, as well as the chosen layout of Fig. 2D, include parallel routes, several of which should be cleared at the same time. This can be accomplished in accordance with the present invention because the energization of the route relay 2-4, for example, is maintained only during the cycle of operation in which it causes the transmission of its route code as determined by the associated route code jumpers in a manner later to be explained. Then, as soon as the route relay 2-4 is dropped out at the end of such cycle of operation, another route relay, for example, route relay 3& may be picked up upon the actuation of the entrance button 3NB followed by the actuation of the exit button 6X3 to cause the associated route to be cleared contemporaneously with the route from the signal 2 to the signal 4.

More specifically, the actuation of the entrance button SNB causes the energization of its repeating relay 3NR through its pick up circuit, after which front contact 16 closes its stick circuit, all as above pointed out. The actuation of the exit button EXB then closes a pick up circuit for the route relay 3-6 from through a circuit including back contact 65 of relay ZNR, front contact 11 of relay 3NR, upper winding of relay 36, back contact 18 of relay BNR, back contact 19 of exit button SXB, to

As soon as the contacts of the route relay 3-6 respond, a stick circuit is closed from (B+) through a circuit including polar contact in a right hand position, front contact 8|, lower winding of relay 3-6, bus wire 10, windings of route stick relay RS, back contact H of relay E, wire 12, front contact 14 of cancel button CA, to (CN).

With the route relay 36 picked up, the starting button ST may be operated to cause the communication part of the system to be initiated into operation for the transmission of the station and route codes determined by the route relay 3-6.

It will be observed that the route stick'relay RS does not pick up untilthe stick circuit for a route relay has been closed, at which time the then. picked up entrance relay NR for the first entrance button actuated is dropped away and all other relays NR are thereby prevented from picking up in response to their associated entrance buttons. In the event that the operator should actuate the entrance button 3NB and then actuate the entrance button BNB by mistake, no route relay is picked up as a result of such an erroneous operation. This is because the same potential is placed on the opposite terminals of the route relay. For example, assuming the entrance relay SNR to be picked up, positive potential from is placed upon the left hand terminal of the route relay 3-6 through back contact 64 and front contact 11;

similarly, with, the route relay BNR picked ..up,.

positive potential is placed upon the right hand terminal of the route relay 36 through back contact 2400f relay am, back contact 24! of relay ENR and front contact 242 of relay GNR. Thus, the route relay 3-6 is prevented from picking up under such circumstances.

Should the operator actuate two entrance buttons, such as 2N3 and 3NB followed by the actuation of the exit button GXB, the .circuits are so arranged that no route relay is picked up under such circumstances. This is because of the interlocked contacts 65 and 11. On the other hand, should the same two entrance buttons be operated followed by the actuation of the eXit button EXB, only the route relay 25 would be picked up. This is also because of the interlocked contacts 65 and H. In other words, the route relays are so interlocked with their exit and entrance controls that only one route relay can be picked up at any one time.

Proposed route indications.-Considering that a particular route relay is picked up, the proposed route is immediately indicated on the control panel by the illumination of the proposed route indicators. With reference to Fig. 4 of the accompanying drawings, the track diagram and control buttons of the control panel is repeated from Fig. 1A. The proposed route indicators have been typically illustrated by the indi cator 23?, which is located in the section of miniature track diagram designated 23 and which entirely illuminates such section when energized. Each of the remaining sections have their respective proposed route indicators P which have been shown in Fig. 4 with preceding numerals indicative of the section with whichthey are associated, but havenot been shown in the sections for the sake of simplicity in the drawings.

The completed route indicators C have preceding numerals corresponding to the miniature track sections with which they are associated, and are typically represented as associated with their respective sections by the indicator lamp 230. These completed route indicators illuminate their entire sections with a color, such as red, to distinguish from the lunar white illumination of the proposed route indicator 23P.

With the route relay 2-4 picked up, for example, its repeating relay 2-4P is energized by a circuit closed through its front contact 243. As soon as the route repeating relay 2--GP is picked up, it has a stick circuit closed depend:

ent upon both signals governing trafiic over such a route in opposite directions remaining at stop. More specifically, a circuit is closed for relay 2- lP from through a circuit including front contact 2 34 of cancel button CA, polar contact 245 of signal indicating relay AGK in a right hand position, polar contact 246 of signal indicating relay ZGK in a lefthand position, front route relay 24P is maintained closed until one of the signals is cleared and is indicated on the proper relay GK, or until the operator effects a a cancellation of such a proposed route by the operation of the cancelling key CA.

As soon as the route has been designated by the picking up of the route relay and its repeating relay, such proposed route is indicated to the operator by the. illumination of the proposed nated by their respective route repeating relays.

Inasmuch as only one route relay can be picked up at any one time, as above explained, only the proposed route indicators for a single route can be illuminated at one time.

Transmission of the selected codes.--After the operator hasthus designated a proposed route by the operation of its entrance and exit buttons and observed such route indicated on the control panel by the proposed route indicators, he can pursue either of two courses; namely, he can cause the route code to be transmitted together with its station selecting code by the actuation of the start button ST, or he can cause the proposed route to be cancelled from the route relays by the actuation of the cancel button CA. The latter course, merely opens the front contact 14 of the cancel button CA dropping the particular route relay picked up and opens the front contact 244 dropping its repeater relay so that the proposed route is no longer illuminated on the miniature track diagram.

However, the operation of the starting button ST to cause the transmission of the selected route code and its station selecting code, initiates the communication system into operation and the transmission of the proper code impulses together with the cancellation or dropping of the particular route relay at the end of such cycle of operation so that another route relay may be picked,

up for a succeeding cycle of operation.

Assuming a proposed route to have been set up on the panel by 3NB and GXB resulting in the energized condition of the route relay 36, the operator causes the code thus selected to be transmitted over the communication system by the actuation of the starting button ST. This closes a pick up circuit for the change repeating relay CHP from through a circuit including back contact 25 of relay SA, back-contact 26 of relay FC, upper winding of relay CI-IP, wire I5, back contact 25! of the starting button ST, to As soon as the relay CI-IP picks up, a stick circuit is closed from through a circuit including back contact of relay LV, front contact 3| of relay CHP, lower winding of relay. CHP, to

The response of the relay CHP' closes a pick up circuit for the control ofiice starting relay C from through a circuit including back contact 28 of relay SA, front contact 29 of relay CHP, Winding of relay 0, to As soon as the relay C picks up, a stick circuit is closed from through a circuit including back contact 32 of relay 2SA, front contact 33 of relay '0, winding of relay 0, to

The picking up of relay C is maintained throughout the cycle of operation inasmuch as the relays SA and ZSA are picked up in that order' so that front contact 28 of the relay SA is closed to apply positive potential to front contact 33 before back contact 32 of 23A opens. However,--'at the end of a cycle of operation, the

relays SAand ZSA drop away in, that order so that the front contact 28 of relay. SA is opened before the back contact 32. of relay 2SA closes, thereby momentarily opening the stick circuit for relay C. I

The picking upof the relay C opens its back contact I65 which prevents the field start relay F from having further opportunity to be picked up duringthe ensuing cycle of operation although the presence of a starting condition may be at thefield station. 1

Thepicking up of the relay C closes front contact II and applies energy to the buses emanating from the stepping'relays which supply energy to the code contacts selected by the particular route relay then picked up.

Before considering the particular characters of the impulses applied in accordance with selections effected; bythe particular picked uproute relay, it isbelieved desirable to point out the manner in which these impulses are impressed upon the control and stepping line circuit.

Energy is supplied to either the bus 4'! or the bus 48 forenergizing' the relays PC or NC respectively depending upon the particular code selection for the first impulse. If the relay PC is picked up, a positive impulse is applied to the stepping and control line circuit from the positive terminal of the control. battery CB through back contact 50 of relay NC, front contact 5| of relay PC, back contact 52 of relay EP, windings of line relay F in the control office, over the control of line II] to the. several field stations including the polar line relay F at the first field station, and then over. the return line I2 to the control ofiice, through front contact 53 of the relay PC, back contact 54 of the relay NC, at the negative terminal of the battery CB.

It will be readily apparent that, if the relay NC is picked up with the relay PC dropped away, the contacts 50 and 54 apply current to the stepping and control circuit in the reverse or negative direction to the flow .of current above pointed out.

The application of an impulse to the stepping line is repeated by the line relays F and causes the half step relays VP to be picked up (see Figs. 5 and 6). The operationof relay VP causes the impulsing relay R. in the control ofiice to be picked up followed by the picking up of its relay EP upon the closure of contact 95. The picking up of the relay EP opens the stepping and control line circuit at back contact 52 causing the first time space.

The deenergizationof the line relays F causes relay EP, so that the control line circuit is again energized upon the closure of back contact 52 in accordance with the then energized condition of the relays PC and NC as determined by the code selecting contacts now rendered efi'ective through front contacts of the relay IV picked up during such first time space period.

Such energization of the control line circuit causes the line relays F and the various relays including the half step relayVP at thecontrol. office and at each of the field stations to respond followed by the picking up of the impulsing relay 'ofiice and at each of the field'stations are picked upduring this second time space period.

This impulsing operation of the stepping and control line circuit continues so as to cause the stepping relays at the control oifice and at the selected station to progress through the complete cycle of operation.

Having discussed briefly how the impulslng is accomplished, we Will now consider how the character of each impulse is determined. The picked up condition of the route relay 3-6 connects its associated code jumpers between the stepping control buses I2I, I22, I23, I24, I25, I26, I21 and I28 and the bus wires 41 and 48 for the control of relays PC and NC respectively, which stepping control buses are successively rendered efiective to. apply the entire control code for the cycle of operation.

The complete control code may be considered as having its code elements or impulses divided into two groups. The first group includes the code elements provided for station selection, while the second group includes the code elements for the particular route to be set up at theselected station. The first element in the route control code is for determining the direction of traffic or the particular route selected, while the next three elements select the particular route, and thelast element is to determine whether such route is to be cleared or put to stop. It is to be understood in this connection, however, that the uses of the elements in the route control code may be arranged in any desired order, inasmuch as the route control code is not rendered effective until after the last code element has been received at the field station.

In order to give a more clear and definite understanding with regard to the manner in which these codes are assigned to the several route relays in the field, a typical code table of the control codes is given below.

Typical code table for controls Field route o selection 35 3-5 stop 3-6 3-6 Stop 3-4 3-4 stop 2-4 2-4 stop 2-5 25 stop 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1+ 1 1 1 1 1 1 1++++++++1 1 1 1 1 1 1 1++++++++ m 1 1 1++++.1 1 1 1++++1 1 1 1++++1 1 1 1++++ 1++1 1++1 1++1 1++1 1++1 1++1 1++1 1++ s +1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+ w With reference to the above code table, it is noted that the station selecting group of code elements are indicated as being the same for all of the: codes shown. However; the first group of codcfilements are contemplated as arranged in a typical Baudot code fashion so as to give a total number of eight station selecting codes for three steps. sixteen for four steps, and thirtytwo for five steps, etc., but for convenience and simplicity in the typical code table only the particular code employed at the field location disclosed in Figs. 2A, 2B, 2C and 2D has been shown, it being understood that each of the remaining station selecting codes may have associated therewith the same route control codes as shown associated with the particular station selecting code chosen for this station. Therefore, if the full capacity of the eight impulse cycle were employed, the code table would show 256 codes.

It will be noted that certain of the codes in the table are employed for route relays, but the remaining codes may be considered as spare codes for which route relays may be added, if the track layout should be enlarged or rearranged to require more route codes.

The relays PC and NC have their right hand terminals connected to while theirleft hand terminals are connected to buses 41 and 48 which extend through the route relay bank of the control machine (see Fig. 1A).

Upon the picking up of the cycle controlling relay C following the picking up of a particular route relay such as relay 3-6, circuit selections are conditioned so that the station selecting code jumpers and the route code jumpers are successively rendered effective to energize the relays PC and NC for the successive impulses of the cycle of operation.

When the relay C picks up following the picking up of the route relay 3o', energy is applied to the code transmitting relay NC by reason of the position of the code jumper IOI by a circuit closed from through a circuit including front contact GI of relay C, back contact I30 of relay IV, back contact I3l of relay 6V, back contact I32 of relay 5V, back contact I33 of relay 4V, back contact I35 of relay 3V, back contact I 35 of relay 2V, back contact I36 of relay IV, code bus IZI, front contact ill of route relay 3-8, code jumper ldI in a lower position, bus 48, winding of relay NC, to This energization of the relay NC impresses a negative impulse upon the line circuit for the first impulse period. By referring to the typical code table, it will be apparent that this negative impulse agrees with the character of the first impulse for station selection for code No. 23.

Upon the picking up of the relay IV during the first time space period of the cycle, contact I36 shifts the application of energy to the code bus I22, which through front contact II2 of route relay 36 allows the code jumper I02 to determine that the second impulse applied to the line circuit shall be positive by energizing the relay PC over bus 41.

Upon the picking up of the relay 2V during the second time space period of the cycle, contact I35 shifts the application of energy to the code bus I23 which through front contact II3 of route relay 3-0 allows the code jumper I03 to determine that the third impulse applied to the line circuit shall be positive by energizing the relay PC over the bus ll.

In this disclosure chosen for the embodiment of the present invention, there are only three station selecting impulses, and it will be found that the characters of these impulses agree with the characters designated in the typical code table.

The remaining impulses of the cycle constitute the route control code and it will be found that these impulses have characters as designated for code No. 23 of the typical code table.

Upon the picking up of the relay 3V during the third time space period of the cycle, the contact I34 shifts the application of energy to the code bus I24 which through front contact II4 of route relay 3 6 allows the polar contact I04 of relay 3% in a right hand position to determine that the fourth impulse applied to the line circuit shall be negative by energizing the relay NC over the bus 38.

Upon the picking up of the relay 4V during the fourth time space period of the cycle, contact I33 shifts the application of energy to the code bus I25 which through front contact N5 of route relay 3-45 allows the code jumper I 05- to determine that the fifth impulse applied to the line circuit shall be positive by energizing the relay PC over the bus 41.

Upon the picking up of the relay 5V during the fifth time space period of the cycle, contact I32 shifts the application of the energy to the code bus I26 which through front contact H6 of the route relay 3IS allows the code jumper I06 to determine that the sixth impulse applied to the line circuit shall be negative in character by energizing the relay NC over the bus 48.

Upon picking up of the relay 6V during the sixth time space period of the cycle, contact I3I shifts the application of energy to the code bus I27 which through front contact II! of route relay 3-6 allows the code jumper I01 to determine that the seventh impulse applied to the line circuit shall be negative by energizing the relay NC over the bus 48.

Upon the picking up of the relay IV during the seventh time space period of the cycle, contact I30 shifts the application of energy to the code bus I28 which through front contact II8 of the route relay 36 allows the code contact I08 of the stop route relay SR to determine that the eighth impulse applied to the line circuit shall be positive in character by energizing the relay PC over the bus 41.

Thus, the route relay 36 determines the char acters of the impulses for a cycle of operation for clearing a route from the signal'3 to the signal 6.

If the operator, after having cleared this route, desired to return it to stop, because of a change in his plans for the oncoming train, he first actuates the stop button STP and then identifies the route by the operation of the entrance and exit buttons for that route. Operation of button STP closes an energizing circuit for the stop route relay SR from through a circuit including back contact of stop'button STP, wire I31, back contact I38 of relay RS, windings of relay SR, back contact 96 of relay E, wire 82, front contact 83 of cancelled button CA, to As soon as the relay SR picks up it closes a stick circuit from through a circuit including front contact I39 of relay SR, windings of relay SR, back contact 96 of relay E, wire 82, front contact 83 of cancel button CA, to

The operator then actuates the entrance button 3N3 in a clockwise direction to its operating position followed by the actuation of the exit button BXB which accomplishes the energization of the route relay 3 6, as above described. Then, upon the actuation of. the starting button ST, the system is set into operation for 

